Tokyo Electric Power Co. said three more workers at its crippled Fukushima Dai-Ichi nuclear power plant were exposed to radiation exceeding the government’s annual limit.

The male workers, in their 20s, were exposed to levels beyond the limit of 250 millisieverts, Junichi Matsumoto, a general manager at the utility known as Tepco, told reporters in Tokyo today. Medical examinations showed the exposure had no immediate impact on their health, he said.

Under Tepco rules, a worker exposed to more than 170 millisieverts will be deployed to the plant’s radiation- and quake-proof operation center, Hajime Motojuku, a spokesman for the utility, said by phone. A worker exposed to more than 200 millisieverts will be sent to other Tepco plants or offices, according to Motojuku.